The black wire goes to one screw, the white wire to the other one.

It does not matter which is which.

As retarded as it sounds, a switch that controls a light from only one location is a "two-way switch". Don't ask. Electricians call it a 2-way, electronics nerds call it SPST.

Two locations use two 3-way, or "SPDT" switches

Three or more locations are the same as two, except that, in between them are added one or more "4-way" or "really-weird-wired DPDT" switches.

Thanks for the reply, pharkus. I usually encounter switches with black and red wires (middle run and three-way). Not used to finding a white (neutral) wire actually wired to the switch.

Bubba-
The white is not a neutral in this situation-
It should really be remarked with black tape to indicate it is a switch wire in the black run to the light.

Pharkus, do they really call a SP switch a "2-way" where you are? I have never heard that before.
We just call 'em "single pole".

OK Let me try to make this easy and clear this up for some of you. I am a electrician and do this for a living. First of all the switch is called a "Single Pole Switch" , it is not a 3 way switch. A 3 way switch is a minimal of 2 switches like in your hallways one on each end. These are 3 way switches and are completely diff than a single pole switch. How to identify the to is simple. A single pole "one way" switch will read on/off on the switch. A 3way switch does not read anything. Also a 3way switch works with a little something called travelers... OK not that is clear lets move on. On a single pole switch it does not matter with wire you put on each side of the switch because they are both hot! Yes I said BOTH;] There is no neutral that connects to the switch. It makes up at the lighting fixture or in the nailon (switch box) not to the switch itself. The wire that is commonly mistaking for a neutral because it is (WHITE) is called a switch leg. In the box you will find 2 or 3 wires pending on if a ground was used.. A constant hot being one(BLACK USUALLY) BE CAREFUL messing with this! The 2nd (Usually a white wire) is the switch leg. This is the wire that once the switch is flipped, sends the current to the fan/light/device/etc. You may come across 2 black wires in the box or a black and a Red. Just remember one is CONSTANTLY HOT and the other is only HOT(energized) when the switch is flipped. The bare wire (OR GREEN) wire you should also see in there is your ground and hooks to the top terminal usually colored green. I hope this helps to better explain things. Please Turn OFF the BREAKER when doing this and use a "HOT STICK" to insure the power is off or that it is not back feed from another device.

Take Care
ElectricMan

In England, "Ways" refers to the number of current carrying conductors used in the switching action(s). A single pole switch could be called a 2 way since it only uses 2 conductors, but most of the other sparkies I know call them single poles.

Well there is no such thing as a 2 way switch. Its simply a single pole. No where in the Code book does it refer to a "2 way." It does not exist.. If anything if would be a one way, cuz it only works one way.. ;]

Thanks for all of the information, guys. This forum never fails to educate me. It does show me that there is a lot more to learn about electrical issues than one might find in DIY guides. As always, a special thanks to the eletricians that also take the time to add their knowledge and skills.

"The wire that is commonly mistaking for a neutral because it is (WHITE) is called a switch leg. In the box you will find 2 or 3 wires pending on if a ground was used.. A constant hot being one(BLACK USUALLY) BE CAREFUL messing with this!"

Generally, in a cable assembly (like romex), the white wire is used to feed the switch and it must be reidentified per NECarticle 200.7(C)(3)

The wire that is commonly mistaking for a neutral because it is (WHITE) is called a switch leg. In the box you will find 2 or 3 wires pending on if a ground was used.. A constant hot being one(BLACK USUALLY) BE CAREFUL messing with this! The 2nd (Usually a white wire) is the switch leg.

No that is incorrect. The constant hot will be the remarked white, the switched hot will be the black. If you were really an electrician, you would know that.

I'm with dezwit and normel on this one. White is used as the constant hot, and black as the switched, so as to avoid the situation where, at the fixture, two white wires are attached to the device being switched.

Many 2-way switches (I'm still gonna call them that, you won't stop me, and it's not WRONG. Get over it.) are labeled as such when you buy them. Head on down to your local hardware or electrical supply store, I bet you will see many SPST switches labeled as "2-way". Yes, they are also called "single-pole", but an SPDT or "3-way" switch is also single-pole. That's what SPDT stands for: "Single-Pole, Double-Throw". One switched pole, two active positions.

Let us not forget that automotive people call your contactors "solenoids" (even though the name also and more appropriately refers to part of the starter), and us electronics nerds call them "big-arse relays". There's a ton of different names for the same thing and none of us are qualified to call any of them "wrong" unless the term more accurately refers to something else.

Look at any elementary wiring how-to book under "switch beyond light". It tells you to splice the incoming hot (black) to the white wire of the switch leg and mark it with a black permanent marker or tape to avoid confusion.

The purpose is to end up with a free white and black to connect to the lamp fixture so that the black of the fixture is hot and on the center button, not the shell of the socket.

billhart you are referring to a crazy joint which is made up at the fixture itself. The OP is asking about a SWITCH, not making joints at the fixture.. USA style! Im not Canadian. This is not rocket science and im not going to play top electrician with you people either.

(OP)
Call and electrician in you phone book and ask them and you can determine the hacks in this forum from the people that know what they are talking about.

The OP was talking about a switch at the end of a run, beyond the light. He got his questions answered.

Then electricman posted a lot of words including an assertion that the constant hot in the switch box would be black and the switched leg white. That is not how it is supposed to be done. Dezwit, normel, Pharkus, and I have all pointed out that it is wrong. The reader can take their pick of whose advice to follow.

Actually the black would be the hot wire. The white wire which becomes "hot" is known as a switch leg. Electricman is correct on this one. You do not have to color the wire black or phase it black either. Its simply known to be only energized when the switch is flipped. Im referring to only the switch and switch box here, not the actual fixture. Though at the fixture the black from the device (fan/light)would make up with the white(switch leg) from the switch and the white(neutral) at the fan returns to the panel.

Phase taping or painting of a white conductor that is being used as a switch leg has been an NEC requirement since 1999. As pointed out by others, the code requires that when the white wire is used in a switch leg, it must be the hot wire and not the return.

Ok this was about a switch right? Not phasing a 480v panel right? What article can I read that a switch leg must be phased. Not that it is relevant to the question at hand but for my own curiosity.

WRONG! The white wire MUST be the feed to the switch! (the constant hot). This is not just a common practice, it is the code! Article 200.7(C)(2). Any electrician SHOULD know this!

Article 200.7 Use of Insulation of a WHITE or GRAY color or with THREE continuous white stripes.

What does this have to do with phasing a wire or anything about the switch. Another irrelevant post...

tom
Where does it say anything about using a return AT THE SWITCH.. The neutrals make up at the Fixture, or in the switch box JUST PASSING THROUGH if in the switch box. What country are you wiring in. Here In Tennessee BLACK IS THE CONSTANT HOT right from the panel, to the switch. A switch has no neutral, the device does. This is TOOO funny.

Keep reading. I quote from NEC 1999 but from what I've heard it is the same in later editions.

200-7 (c) The use of .. white ...etc for other than a grounded conductor ... shall be permitted only as in (1) through (3)
(1) If part of a cable assembly and where the insulation is permanently re-identified to indicate its use as an ungrounded conductor, by painting or other effective means ... at each location where the conductor is visible and accessible.
(2) Where a cable contains an insulated conductor for single-pole, 3-way, or 4-way switch loops, and the conductor with white... insulation ... is used for the supply to the switch but not as a return conductor from the switch ...

So code recognizes this practice, which as I pointed out earlier is usually illustrated in the how-to books for a switch beyond a light.

"What does this have to do with phasing a wire or anything about the switch. Another irrelevant post... "

Are you serious??

Article 200.7(C)(2).

Where a cable assembly contains an insulated conductor for a SINGLE POLE, 3-way or 4-way switch loops and the conductor with white or gray insulation or a marking of three continuous white stripes IS USED FOR THE SUPPLY TO THE SWITCH BUT NOT AS A RETURN CONDUCTOR from the switch to the switched outlet. In these applications the conductor with the white or gray insulation or with three continuous white stripes shall be permanently re-identified to indicate its use by painting or other effective means at its terminations and ay each location where the conductor is visible and accessible.

yes i know all that part though that is if you USE THE WHITE AS THE HOT IT MUST BE PHASED AT THE SWITCH AND PANEL.. Not as just a return for the switch leg. Anyway whatever. Ive never had a inspector say anything about that to me and Im reading this out of 2008 NEC codebook and it only refers to phase a wire at termination Switch/Panel IF the white is main source of power. Not the actual leg itself. I maybe reading that wrong but I have never had a problem with it.

I interpret 200.7(C)(2) as excluding switch loops from 200.7(C)(1), but I'm fairly new to this reading-code BS.

It would seem to me that, if switch loops are SPECIFICALLY mentioned in (2), then (1) does not apply to them. Further, (1) would, at first, seem to include (2). Nobody would bother to write (2) if (1) still applied.

The REASON for using white as the supply is simple. Say you've got the hot coming into the fixture box, and just feeds through, staying black to the switch. Return from the switch is now white. Neutral from the supply is also white. Now you have two white wires to connect to the fixture.

Hypothetically, remove the fixture, and have another electrician come reinstall it, with the power turned off. How does the new electrician ever figure out which white wire is hot?

By using the white wire as the supply TO the switch, the hot wire that needs attaching to the fixture is black, and easily identified. Problem solved.

And who do you think you're calling a hack?

Why would you use the white wire and phase both ends black, when u already got a black wire there in the romex?

The only white part of the switch leg you will see is about 6 inches of wire hidden behind the switch which doe not need to be phased. Ever heard the term "Light Leg" meaning white in color.

A electrician would use a hot stick or meter to determine the hot wire... Not that it would be needed because obviously the white wire from the switch to the device is the leg and the white(s) from the home run and the fan at twisted together. When did I call you a hack? This site is a bunch of wannabes that have old out dated code books "do it yourselves that do not know what they are talking about for the most part and want to quote the code book to make them look like they know whats up. Pull the switch out of the wall and just look at if and you will see the black is incoming hot from the panel, not the white. Im done. This site needs moderator to keep people like yourself from trying to teach something you know nothing about. White wire is Neutrals and switch legs only. End of story. Go pull some white wire in a commercial build as all your hots and blacks for legs and see how fast the JW kicks you off the job site! Look at the open your panel and look at the branch circuits.. WOW they are all black. Look at the Neutral bar hurm.. all white!! Look at the grounding bar..hurm all bare copper there unless its bonded then you will find white wire and bare copper.

Why use the white as hot? That's been explained at least twice in this thread. It is so you have a hot black to connect to the lamp fixture, assuring that the shell of the lamp socket is on the (only) white.

Nobody here is suggesting that you run white wires as hot in any situation EXCEPT to feed the switch as specifically allowed in the code.

Give it up. This reminds me of a quote: "I refuse to engage in a battle of the wits with an unarmed man".

Can anyone remember who said it? (Googling no fair).

lol, Well people do things differently. This is the 1st I have ever heard of this EVER. Is this required or allowed? Like I said I have never had a inspector say a word to me about this. Also could this be due to state or county?

brianwarner, I think the reason an inspector never says a word about it is because nobody really cares. This is one of those "technicality" things.

In my example above, I stated that your new electrician has to do the work with the power off. I'll add that the new electrician may very well be a DIYer. You cannot deny that it will be a lot simpler if one fixture wire is black and the other is white.

I do not consider my 2008 NEC to be outdated.

I come from an electronics background. Personally, I would prefer the constant hot to be black, as you are insisting. That would be my preference, because, with the switch off, the constant-hot is "more hot" than the switched hot (which will be 0V through the resistance of the load). I was corrected on it numerous times and ended up looking in the book myself, to find out that I was (and you are) wrong. I've never been "called on it" either -- except in a couple online forums, this one included. Ultimately, "my preference", "marilynmanson's preference", "general practice", and "code" are four entirely different things that may not always be equal.

I have pulled apart many switch loops - and those are all we're talking about: switch loops - and found white to be the constant hot.

I am still undecided on whether the white is REQUIRED to be the constant. I personally would prefer to believe it's not, although it looks as though it is. I do know, for sure, as I am staring at it myself, that it is _definitely_ allowed.

Please don't forget that a lot of sections of code exist in order to reduce the likelihood of error - either by electrician or DIY - down the road. There is no scientific reason to care which wire is constant and which one is switched. They are BOTH "hot" when the switch is ON, and the switch leg is officially "floating" when it is off. Neither is ever "neutral" or "grounded", and therefore, other than the aforementioned exceptions in 200.7(C), neither wire has any right to be white.

Before 2005 you could use an UNMARKED white wire in a cable that was a switch loop for the power feed (but not the return from the switch).

In 2005 and later, you MUST remark it.

Pharkus is right, the WHITE must be the feed to the switch not the return.
Don't know the justification, but that's the way the code has read for as long as I've been around.

To me the code change is sort of goofy. They should have just deleted the #2 exemption which would fall back to the #1 requirement of always requiring remarking.

I suspect brian's point of view comes from being an industrial electrician who does everything in conduit. Then of course you wouldn't pull a white wire for anything except neutral.

But with NM (Romex) you've got the white and need to do something with it so the custom has evolved, now enshrined in code language, of using the black for switched hot and white for constant hot in this particular situation.

Now that marking is required, in hindsight it would have made more sense to require the white to be marked and used for switched hot, so the black was always constant hot. But it didn't evolve that way and would create still more confusion to change.

As I said, since the wire has to be remarked anyhow, I'm not sure why exemption 2 exists at all and what difference it makes which way you connect it.

Of course, switch loops are by and large going away. Modern fancy lighting controllers are replacing switches and require a neutral to work.

Just manufacture "switch-loop cable" with black and red conductors instead of black and white.

Why haven't I seen that yet?

Most of the time I run /3 anyway, leaving a capped-off neutral in the switch box as a degree of future-proofing.

It is quite simple. If your feed for a light goes to the fixture box first then your cable assembly (12/2) from the fixture box to the switch consists of: white (hot from the fixture box to the switch re-identified at both ends),black (return from the switch to the fixture box), and ground (if you don't know then hire a professional).
-See 2005 NEC 200.7(C)(2) Honest, its in there.

This has nothing to do with phasing, or landing wires in the panel or any of the other nonsense posted by some in this thread.
This kind of attitude and false information is just rediculus and should be kept to ones self. It does nothing to contribute to answering the original post.

"White wire is Neutrals and switch legs only. End of story. Go pull some white wire in a commercial build as all your hots and blacks for legs and see how fast the JW kicks you off the job site! Look at the open your panel and look at the branch circuits.. WOW they are all black. Look at the Neutral bar hurm.. all white!! Look at the grounding bar..hurm all bare copper there unless its bonded then you will find white wire and bare copper."

Wrong, wrong wrong, it is in the code, read it for yourself. Just because you have never read it or had it brought to your attention does not give you the right to stomp all over someone else's post. Especially when you don't have all the facts. And have apparently been installing switches illegally for who knows how long.

Every trade develops its own jargon. Sometimes different sectors or geographic areas develop different jargon. We appear to have that underlying some of the discussion here.

The term Phasing would appear to derive from marking the phases of a 3-phase system with colors that are at least locally standard. He then applies the term to the reidentification of conductors on what the code would call single phase systems having two different hot wires.

This may be common terminology among Brian's industrial coworkers, but is not used among a lot of people doing house wiring in other parts of the continent.

This does not make the term exactly "wrong" but it hinders communication with people who don't used it, and things would be a lot clearer if everybody recognized it for the specialized jargon it is.